This invention relates to an electric connecting clamp to electrically energize an ignition unit of a model engine used in a remotely controlled model such as a model aircraft or the like.
It is known that the ignition unit of a model engine is ignited by connecting the ignition unit to an electric source through an electric clamp. FIG. 1 shows a known cylindrical electric clamp 3 which incorporates two terminal units 2. The cylindrical electric clamp 3 is not provided with any electric source. It connects the ignition unit to an electric source by means of the terminal units 2 which can be connected to a battery.
FIG. 2 shows another electric clamp 4 which comprises a casing 6 to accommodate a dry cell, a cylindrical clamp member 7 with a split clamping portion 7a, and a movable sleeve 5 disposed around the cylindrical clamp member 7. Both the split portion 7a and the sleeve 5 are provided with bottom flared portions. A helical spring 8 is also disposed around the cylindrical clamp member 7. The cylindrical clamp member 7 is normally placed in a clamping position since the sleeve 5 is biased by the spring 8. It can be placed in a releasing position by moving the sleeve 5 against the spring 8. This electric clamp has some drawbacks. The cell casing of this electric connecting clamp is a closed type, and does not permits replacement of the dry cell so that the clamp has to be discarded when the dry cell is spent. In addition, it is difficult to machine the split clamp portion 7a and the sleeve 5, and to assemble the parts constituting the electric clamp, thereby increasing the manufacturing cost of the electric clamp.